spring mybatis sqlSessionFactory

<!-- 配置Mybatis -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dataSource"></property>
    <property name="configLocation" value="classpath:config/mybatis.xml"></property>
    <!-- <property name="mapperLocations" value="/WEB-INF/conf/mappers/*Mapper.xml"></property> -->
    <property name="mapperLocations">
        <list>
            <value>classpath:config/mappers/**Mapper.xml</value>
        </list>
    </property>
</bean>
<bean id="sqlSessionTemplate" name="sqlSessionTemplate"
    class="org.mybatis.spring.SqlSessionTemplate">
    <constructor-arg index="0" ref="sqlSessionFactory"></constructor-arg>
</bean>
           

在mybatis 配置中經常會發現這樣的配置，但是擷取sqlSessionFactory的時候确實另一個對象 DefaultSqlSessionFactory

為何通過applicationContext.getBean(‘sqlSessionFactory’) 擷取的不是 SqlSessionFactoryBean 了;

問題就是SqlSessionFactoryBean 這個bean實作了FactoryBean接口

public class SqlSessionFactoryBean implements FactoryBean, InitializingBean, ApplicationListener

在調用getBean(‘sqlSessionFactory’)的時候傳回的是 SqlSessionFactoryBean 實作的getObject() 對象;

public SqlSessionFactory getObject() throws Exception {

if (this.sqlSessionFactory == null) {

afterPropertiesSet();

}

return this.sqlSessionFactory;

}

傳回的就是一個sqlSessionFactory 這個 sqlSessionFactory 就是通過的buildSqlSessionFactory() 建構的

protected SqlSessionFactory buildSqlSessionFactory() throws IOException {

Configuration configuration;


XMLConfigBuilder xmlConfigBuilder = null;
if (this.configLocation != null) {
  xmlConfigBuilder = new XMLConfigBuilder(this.configLocation.getInputStream(), null, this.configurationProperties);
  configuration = xmlConfigBuilder.getConfiguration();
} else {
  if (logger.isDebugEnabled()) {
    logger.debug("Property 'configLocation' not specified, using default MyBatis Configuration");
  }
  configuration = new Configuration();
  configuration.setVariables(this.configurationProperties);
}


if (this.objectFactory != null) {
  configuration.setObjectFactory(this.objectFactory);
}


if (this.objectWrapperFactory != null) {
  configuration.setObjectWrapperFactory(this.objectWrapperFactory);
}


if (hasLength(this.typeAliasesPackage)) {
  String[] typeAliasPackageArray = tokenizeToStringArray(this.typeAliasesPackage,
      ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
  for (String packageToScan : typeAliasPackageArray) {
    configuration.getTypeAliasRegistry().registerAliases(packageToScan,
            typeAliasesSuperType == null ? Object.class : typeAliasesSuperType);
    if (logger.isDebugEnabled()) {
      logger.debug("Scanned package: '" + packageToScan + "' for aliases");
    }
  }
}


if (!isEmpty(this.typeAliases)) {
  for (Class<?> typeAlias : this.typeAliases) {
    configuration.getTypeAliasRegistry().registerAlias(typeAlias);
    if (logger.isDebugEnabled()) {
      logger.debug("Registered type alias: '" + typeAlias + "'");
    }
  }
}


if (!isEmpty(this.plugins)) {
  for (Interceptor plugin : this.plugins) {
    configuration.addInterceptor(plugin);
    if (logger.isDebugEnabled()) {
      logger.debug("Registered plugin: '" + plugin + "'");
    }
  }
}


if (hasLength(this.typeHandlersPackage)) {
  String[] typeHandlersPackageArray = tokenizeToStringArray(this.typeHandlersPackage,
      ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
  for (String packageToScan : typeHandlersPackageArray) {
    configuration.getTypeHandlerRegistry().register(packageToScan);
    if (logger.isDebugEnabled()) {
      logger.debug("Scanned package: '" + packageToScan + "' for type handlers");
    }
  }
}


if (!isEmpty(this.typeHandlers)) {
  for (TypeHandler<?> typeHandler : this.typeHandlers) {
    configuration.getTypeHandlerRegistry().register(typeHandler);
    if (logger.isDebugEnabled()) {
      logger.debug("Registered type handler: '" + typeHandler + "'");
    }
  }
}


if (xmlConfigBuilder != null) {
  try {
    xmlConfigBuilder.parse();


    if (logger.isDebugEnabled()) {
      logger.debug("Parsed configuration file: '" + this.configLocation + "'");
    }
  } catch (Exception ex) {
    throw new NestedIOException("Failed to parse config resource: " + this.configLocation, ex);
  } finally {
    ErrorContext.instance().reset();
  }
}


if (this.transactionFactory == null) {
  this.transactionFactory = new SpringManagedTransactionFactory();
}


Environment environment = new Environment(this.environment, this.transactionFactory, this.dataSource);
configuration.setEnvironment(environment);


if (this.databaseIdProvider != null) {
  try {
    configuration.setDatabaseId(this.databaseIdProvider.getDatabaseId(this.dataSource));
  } catch (SQLException e) {
    throw new NestedIOException("Failed getting a databaseId", e);
  }
}


if (!isEmpty(this.mapperLocations)) {
  for (Resource mapperLocation : this.mapperLocations) {
    if (mapperLocation == null) {
      continue;
    }


    try {
      XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(mapperLocation.getInputStream(),
          configuration, mapperLocation.toString(), configuration.getSqlFragments());
      xmlMapperBuilder.parse();
    } catch (Exception e) {
      throw new NestedIOException("Failed to parse mapping resource: '" + mapperLocation + "'", e);
    } finally {
      ErrorContext.instance().reset();
    }


    if (logger.isDebugEnabled()) {
      logger.debug("Parsed mapper file: '" + mapperLocation + "'");
    }
  }
} else {
  if (logger.isDebugEnabled()) {
    logger.debug("Property 'mapperLocations' was not specified or no matching resources found");
  }
}


return this.sqlSessionFactoryBuilder.build(configuration);
           

}

最主要的問題是為何擷取bean的時候調用的是getObejct()

protected Object getObjectForBeanInstance(

Object beanInstance, String name, String beanName, RootBeanDefinition mbd) {

// Don't let calling code try to dereference the factory if the bean isn't a factory.
    if (BeanFactoryUtils.isFactoryDereference(name) && !(beanInstance instanceof FactoryBean)) {
        throw new BeanIsNotAFactoryException(transformedBeanName(name), beanInstance.getClass());
    }


    // Now we have the bean instance, which may be a normal bean or a FactoryBean.
    // If it's a FactoryBean, we use it to create a bean instance, unless the
    // caller actually wants a reference to the factory.
    if (!(beanInstance instanceof FactoryBean) || BeanFactoryUtils.isFactoryDereference(name)) {
        return beanInstance;
    }


    Object object = null;
    if (mbd == null) {
        object = getCachedObjectForFactoryBean(beanName);
    }
    if (object == null) {
        // Return bean instance from factory.
        FactoryBean<?> factory = (FactoryBean<?>) beanInstance;
        // Caches object obtained from FactoryBean if it is a singleton.
        if (mbd == null && containsBeanDefinition(beanName)) {
            mbd = getMergedLocalBeanDefinition(beanName);
        }
        boolean synthetic = (mbd != null && mbd.isSynthetic());
        object = getObjectFromFactoryBean(factory, beanName, !synthetic);
    }
    return object;
}
           

如果對象沒有實作 FactoryBean 就直接傳回了，實作了還需要做處理

if (!(beanInstance instanceof FactoryBean) || BeanFactoryUtils.isFactoryDereference(name)) {

return beanInstance;

}

具體debug可以參考AbstractBeanFactory.getObjectForBeanInstance()

那麼我們如何擷取真正的SqlSessionFactoryBean了

第一種方式

context.getBean(“&sqlSessionFactory”);

注 前面添加了&的都是事先了FactoryBean類的

第二種方式

context.getBean(SqlSessionFactoryBean.class)

如果要擷取所有的FactoryBean

context.getBean(FactoryBean.class);

//擷取所有實作了 FactoryBean.class 的接口 可以看出列印的名稱都是添加了&類似的

String[] fbeans =context.getBeanNamesForType(FactoryBean.class);

for (int i = 0; i < fbeans.length; i++) {

System.out.println(fbeans[i]+”—-“+context.getBean(fbeans[i]));

}

//輸出結果如下：

&sessionFactory—-org.springf[email protected]11e0d39

&sqlSessionFactory—[email protected]

&captchaStoreProxy—-org.springframework.aop.framework.ProxyFactoryBean: 1 interfaces [com.octo.captcha.service.captchastore.CaptchaStore]; 1 advisors [org.springframework.aop.support.NameMatchMethodPointcutAdvisor: advice [[email protected]]]; targetSource [SingletonTargetSource for target object [[email protected]c5b1e]]; proxyTargetClass=false; optimize=false; opaque=false; exposeProxy=false; frozen=false

&clearStatisticsMethod—-org.sprin[email protected]18224bf

&startQuertz—[email protected]b72

&insuranceKbase—[email protected]71

&insuranceKsession—-org.dro[email protected]36dbaa

&orderKbase—[email protected]2bb

&orderKsession—-org.dro[email protected]ea4019

&defaultCache—[email protected]